The present invention generally relates to a water closet and more particularly to a flush water arrangement to minimize the amount of water expended during the flushing operation.
A water closet typically includes a flush tank, a bowl, and a siphon trap to discharge waste from the bowl and prevent gases and waste water from flowing back into the bowl. Efficient water closet performance is a balance between that volume of falling water needed to fill the bowl, either directly from the tank or indirectly from a flush rim which encircles the bowl, and the rate of flow of flush water into the trap required to start and maintain a vacuum in the siphon trap during the flush operation.
Residential homes and buildings are typically equipped with only a single water supply system providing only potable water, irrespective of the uses intended thereof by the resident. Water conservation is now important, especially in the various sunbelt states, and unnecessary consumption of potable water from water closet usage represents an area where water conservation can be achieved. For example, while a typical U.S. water closet consumes about 3.0 gallons of flush water, a conventional European water closet is more water efficient and only uses about 1.5 gallons of water in a thrust-type flushing action. However, this thrust-type action lacks a swirling action which is necessary to clean the interior sidewalls of the bowl. A desirable water closet would efficiently utilize the lower amount of water without sacrificing the benefits gained by thrust and swirling action imparted by the flush water.
One approach to save water is to make the water closet smaller and equip the closet with restrictors to limit the flush water from the tank and thereby render the flushing water more effective. While use of a separate device constitutes a step in the right direction, it would be desirable to have a self-contained water closet which reduces the amount of water required per flush by making the flushing operation more efficient.
A slow discharge of waste has a further unexpected disadvantage. As the discharge leaves the closet it must travel a significant distance to reach the community sanitary system. If the sewage pipes are too great in diameter, the waste will not fill the pipe and tend to form on the pipe wall, resulting in clogged lines. A faster discharge will obviate this situation by acting to scrub the pipe walls.
Accordingly, an object of the invention is provision of a water closet which efficiently uses a substantially reduced head of flush water that cleans the bowl without appreciably affecting the flushing action of the water being discharged and without raising the average head under which this smaller amount of flushing water is delivered.
In accordance with this invention there is provided a water closet including a frusto-pyramidal flush tank expanding vertically downwardly, a downwardly converging bowl including a top flushing rim section receiving flush water from the tank and a lower outlet opening for discharging waste material from the bowl, a conduit for supplying fresh flush water from the tank to the bowl, and a trapway connecting the lower outlet of the bowl to the discharge opening, the bottom part of the bowl and trapway forming a water trap for the sealing function. The trapway forms a continuous passageway described by a specially configured inverted "U" which includes an upleg portion which extends vertically upward from an orifice that defines a contracting expanding nozzle where connected to the bowl outlet, a transition portion which defines the free water level in the main part of the bowl, and a downleg portion which snakes vertically downward from the transition to a discharge opening whereby to pass the waste from the closet. The rim section rapidly supplies fresh flush water to the bowl in a vortex motion to center the waste for entrance into the trapway. The orifice adjacent the bowl outlet communicates waste from the water trap and increases the velocity of the effluent from the bowl. Thereafter, the upleg passage expands in cross-section to receive all waste discharged from the bowl. The transition portion is reduced in cross-section to rapidly become filled and create a siphon in the downleg. As the waste material travels down the downleg the passage expands to form an expansion chamber and then contracts to form an orifice adjacent the discharge opening, the chamber cooperating with the downleg to impart a swirling movement in the waste flow to prevent entry of air into the downleg orifice which could break the siphon action.
Advantageously, the upleg portion allows the waste to be accelerated from the bowl ahead of the flush water with the flush water head rapidly emptying into the bowl to provide the acceleration. Provision of an expansion chamber adjacent the inlet and outlet, respectively, surprisingly allows the siphon action to initiate sooner and not be disturbed during the flushing. This results in substantially less flush water being required for a like flush.
Slow flush water input develops less siphon action in the trap resulting in the waste in the bowl water trap tending to rise to the top of the free surface of the water in the bowl and be the last to be discharged from the bowl. Advantageously, the downwardly converging bowl with the slotted water feed rim rapidly imparts a swirling action to scrub the bowl wall and center the waste for discharge, and the area increase in the upleg, adjacent the transition portion of the closet, defines an expansion chamber that assists in rapid movement of waste material to fill the downleg and start the siphon. The expansion chamber in the downleg adjacent the discharge opening imparts a swirling movement to the waste to prevent turbulence in the flush water, thereby inhibiting air which could break the siphon from entering the downleg.
Other advantages and features will become apparent from the following specification taken in connection with the accompanying drawings.